The invention relates to a method for making patterned paper, in which method the paper is made in a paper machine and patterned.
The invention further relates to an apparatus for making patterned paper, which apparatus comprises a paper machine and a patterning means for paper.
Some paper grades are patterned with various patterns before the paper is delivered to its user. The patterns may be used for aesthetic purposes, for communicating necessary informationxe2x80x94in the packaging, for instancexe2x80x94or for some other purpose. In this application, patterning refers to both text and images.
In prior art, paper is patterned in a separate work phase. For instance, patterned baking paper is made by first making the paper in a paper machine, and then transferring the paper to a separate patterning unit in which patterning is typically done by printing. In a third phase, the paper is siliconized, i.e. coated with silicone which gives the paper the good detaching properties typical of baking paper. Patterning must be done prior to siliconizing so as to have the color stick permanently to the paper. The manufacturing process thus comprises three phases which are all done with different machines and possibly in different factories or even in different localities, and between the phases, the paper reels need to be moved and stored. The manufacturing process in its entirety is, therefore, expensive and complex as it is time-consuming and requires several different machines and work phases. In addition, changing the patterns for the paper is time-consuming, and consequently, the patterning of small batches of paper with special patterns, for instance, is not economically profitable.
It is an object of the present invention to provide a method and an apparatus for making patterned paper, in which the above-mentioned drawbacks do not exist.
The method of the invention is characterized in that a patterning unit is arranged in a paper machine, and a printer belonging to said patterning unit patterns the paper web being made in said paper machine.
An apparatus of the invention is characterized in that the patterning means comprises a printer arranged to the patterning unit arranged in the paper machine, and that the printer is arranged to pattern the paper web being made in said paper machine.
The essential idea of the invention is that a patterning unit is arranged in a paper machine making the paper to be patterned, and the patterning unit patterns desired patterns in to the paper web running in the paper machine. Further, the idea of a preferred embodiment is that the patterning unit comprises one or more printers, whereby the rate of patterning or complexity of patterns can be increased. The idea of another preferred embodiment is that the printer is preferably an ink-jet printer which comprises one or more printing heads, thus making the patterning especially easy. The idea of a third preferred embodiment is that a coating unit is arranged in the paper machine after the patterning unit in the direction of travel of the paper web, and the already patterned paper web is coated at the same time with making and patterning it. The idea of a fourth preferred embodiment is that the patterned and coated paper is a siliconized baking paper.
The invention provides the advantage that paper patterning is performed at the same time and in the same apparatus as paper making, whereby making patterned paper becomes fast. The paper need not be transferred away from the paper machine for patterning, thus avoiding transporting, storing and other extra intermediate phases, which reduces considerably the manufacturing costs and lead-time of patterned paper. Even complex patterns can easily and simply be patterned on the paper, and the patterns can be changed and altered even during patterning through a control program of the patterning unit. Further, a preferred embodiment provides the advantage that by coating the patterned paper immediately after the patterning by means of a coating unit arranged in the paper machine, it is possible to further reduce transport and storage costs and speed up the manufacturing process. In addition, by immediate coating, the patterns are right away covered under the coating and cannot wear or otherwise deteriorate before delivery to the customer.